diff --git a/tests/registration/00-simple.t b/tests/registration/00-simple.t
index 6d93245226e..a8be523e6f3 100755
--- a/tests/registration/00-simple.t
+++ b/tests/registration/00-simple.t
@@ -14,6 +14,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 #------------------------------------------------------------------------------
 # Test suite registration
 
@@ -23,33 +24,22 @@ export RND_SUITE_RUNDIR
 export CYLC_RUN_DIR="$(cylc get-global-config --print-run-dir)"
 
 function make_rnd_suite() {
-    RND_SUITE_NAME=$(< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c6)
-    RND_SUITE_SOURCE="$TEST_DIR/${RND_SUITE_NAME}"
+    RND_SUITE_NAME=x$(< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c6)
+    RND_SUITE_SOURCE="$PWD/${RND_SUITE_NAME}"
     mkdir -p "${RND_SUITE_SOURCE}"
     touch "${RND_SUITE_SOURCE}/suite.rc"
     RND_SUITE_RUNDIR="${CYLC_RUN_DIR}/${RND_SUITE_NAME}"
 }
 
 function purge_rnd_suite() {
-    RND_SUITE_SOURCE=${1:-RND_SUITE_SOURCE}
-    RND_SUITE_SOURCE=${2:-RND_SUITE_RUNDIR}
+    RND_SUITE_SOURCE=${1:-$RND_SUITE_SOURCE}
+    RND_SUITE_RUNDIR=${2:-$RND_SUITE_RUNDIR}
     rm -rf "${RND_SUITE_SOURCE}"
     rm -rf "${RND_SUITE_RUNDIR}"
 }
 
 . "$(dirname "$0")/test_header"
-set_test_number 36
-
-init_suite "${TEST_NAME_BASE}" <<'__SUITE_RC__'
-[meta]
-    title = the quick brown fox
-[scheduling]
-    [[graph]]
-        R1 = a => b => c
-[runtime]
-    [[a,b,c]]
-        script = true
-__SUITE_RC__
+set_test_number 37
 
 # Use $SUITE_NAME and $SUITE_RUN_DIR defined by test_header
 
@@ -164,6 +154,66 @@ contains_ok "${TEST_NAME}.stdout" <<__ERR__
 ${RND_SUITE_SOURCE}
 __ERR__
 
+purge_rnd_suite
+purge_rnd_suite "${RND_SUITE_SOURCE1}" "${RND_SUITE_RUNDIR1}"
+
+#-----------------------
+# Test alternate run dir
+# 1. Normal case.
+TEST_NAME="${TEST_NAME_BASE}-alt-run-dir"
+make_rnd_suite
+ALT_RUN_DIR="${PWD}/alt"
+run_ok "${TEST_NAME}" \
+    cylc register --run-dir="${ALT_RUN_DIR}" "${RND_SUITE_NAME}" "${RND_SUITE_SOURCE}"
+contains_ok "${TEST_NAME}.stdout" <<__OUT__
+REGISTERED ${RND_SUITE_NAME} -> ${RND_SUITE_SOURCE}
+__OUT__
+run_ok "${TEST_NAME}-check-link" test -L "${RND_SUITE_RUNDIR}"
+run_ok "${TEST_NAME}-rm-link" rm "${RND_SUITE_RUNDIR}"
+run_ok "${TEST_NAME}-rm-alt-run-dir" rm -r "${ALT_RUN_DIR}"
+purge_rnd_suite
+
+# 2. If reg already exists (as a directory).
+TEST_NAME="${TEST_NAME_BASE}-alt-exists1"
+make_rnd_suite
+ALT_RUN_DIR="${PWD}/alt"
+mkdir -p "${RND_SUITE_RUNDIR}"
+run_fail "${TEST_NAME}" \
+   cylc register --run-dir="${ALT_RUN_DIR}" "${RND_SUITE_NAME}" "${RND_SUITE_SOURCE}"
+contains_ok "${TEST_NAME}.stderr" <<__OUT__
+SuiteServiceFileError: Run directory '${RND_SUITE_RUNDIR}' already exists.
+__OUT__
+purge_rnd_suite
+
+# 3. If reg already exists (as a valid symlink).
+TEST_NAME="${TEST_NAME_BASE}-alt-exists2"
+make_rnd_suite
+ALT_RUN_DIR="${PWD}/alt"
+TDIR=$(mktemp -d)
+mkdir -p $(dirname "${RND_SUITE_RUNDIR}")
+ln -s "${TDIR}" "${RND_SUITE_RUNDIR}"
+run_fail "${TEST_NAME}" \
+    cylc register --run-dir="${ALT_RUN_DIR}" "${RND_SUITE_NAME}" "${RND_SUITE_SOURCE}"
+contains_ok "${TEST_NAME}.stderr" <<__OUT__
+SuiteServiceFileError: Symlink '${RND_SUITE_RUNDIR}' already points to ${TDIR}.
+__OUT__
+purge_rnd_suite
+rm -rf "${TDIR}"
+
+#-----------------------------------------------------------------------------
+# Now use a real suite
+
+init_suite "${TEST_NAME_BASE}" <<'__SUITE_RC__'
+[meta]
+    title = the quick brown fox
+[scheduling]
+    [[graph]]
+        R1 = a => b => c
+[runtime]
+    [[a,b,c]]
+        script = true
+__SUITE_RC__
+
 run_ok "${TEST_NAME_BASE}-val" cylc validate "${SUITE_NAME}"
 
 run_ok "${TEST_NAME_BASE}-print" cylc print
@@ -182,45 +232,5 @@ else
     fail "${TEST_NAME_BASE}-print.stderr"
 fi
 
-# Test alternate run dir.
-# 1. Normal case.
-TEST_NAME="${TEST_NAME_BASE}-alt-run-dir"
-SRC_DIR="${PWD}/foo"
-REG="${SUITE_NAME}-foo"
-RUN_DIR="${CYLC_RUN_DIR}/${REG}"
-ALT_RUN_DIR="${PWD}/alt"
-mkdir "${SRC_DIR}"; touch "${SRC_DIR}/suite.rc"
-run_ok "${TEST_NAME}" cylc register --run-dir="${ALT_RUN_DIR}" "${REG}" "${SRC_DIR}"
-contains_ok "${TEST_NAME}.stdout" <<__OUT__
-REGISTERED ${REG} -> ${SRC_DIR}
-__OUT__
-run_ok "${TEST_NAME}-check-link" test -L "${RUN_DIR}"
-run_ok "${TEST_NAME}-rm-link" echo foo ## rm "${RUN_DIR}"
-run_ok "${TEST_NAME}-rm-alt-run-dir" echo foo ## rm -r "${ALT_RUN_DIR}"
-## rm -r "${SRC_DIR}"
-
-# Test alternate run dir.
-# 2. If reg already exists (as a directory).
-TEST_NAME="${TEST_NAME_BASE}-alt-exists1"
-mkdir "${RUN_DIR}"
-mkdir "${SRC_DIR}"; touch "${SRC_DIR}/suite.rc"
-run_fail "${TEST_NAME}" cylc register --run-dir="${ALT_RUN_DIR}" "${REG}" "${SRC_DIR}"
-contains_ok "${TEST_NAME}.stderr" <<__OUT__
-SuiteServiceFileError: Run directory '${RUN_DIR}' already exists.
-__OUT__
-## rm -r "${SRC_DIR}" "${RUN_DIR}"
-
-# Test alternate run dir.
-# 3. If reg already exists (as a valid symlink).
-TEST_NAME="${TEST_NAME_BASE}-alt-exists2"
-mkdir "${SRC_DIR}"; touch "${SRC_DIR}/suite.rc"
-mkdir "${PWD}/target"
-ln -s "${PWD}/target" "${RUN_DIR}"
-run_fail "${TEST_NAME}" cylc register --run-dir="${ALT_RUN_DIR}" "${REG}" "${SRC_DIR}"
-contains_ok "${TEST_NAME}.stderr" <<__OUT__
-SuiteServiceFileError: Symlink '${RUN_DIR}' already points to ${PWD}/target.
-__OUT__
-## rm -r "${SRC_DIR}" "${PWD}/target"
-
 purge_suite "${SUITE_NAME}"
 exit